206 On the Trap Tuff of the Connecticut Valley. 



rocks of the valley into their present position ; and that the tufa- 

 ceous traps had previously been protruded and consolidated. It 



principal 



ma 



pposed, part 



have been done in some modern examples. And, indeed, the 

 fact that a portion of the turfaceous conglomerates contains really 

 rounded masses of solid trap, shows at least that a good deal of 

 that rock existed in order to furnish these materials. And it 

 must have been more or less above the water in order that the 

 currents should tear up and wear its fragments. This might in 

 part have been done by igneous agency, as the masses were 

 driven upwards through the fissure ; yet they appear to me for 

 the most part, to have been acted upon by water. And it is a 

 curious fact that the ripple marks, in some places, show that the 

 current was southerlv. as it now is. 



Tilting of the Sandstone Formation Generally. 



We 



reasonings, to a probable solution of the question concerning the 

 relative age of the trap and sandstone of the Connecticut valley. 



appears that all the thick bedded sandstone 



constituting at least one-half, was deposited before the protrusion 



of any trap. 



and 



precursors 



upper 



were being deposited ; and last of all, the principal trap ranges 

 emerged with considerable disturbance of the sandstone. But I 

 have shown that the general dip of that rock, extending through 



trap. Was 



upheaving 

 reasons 



».~f, rU i»i,ivsii. «,, mc iunuvviug reasons:—- 



In the first place, if originally deposited with its present dip, 

 the west side of the valley must have formed the shore of the 

 ocean, and the materials have been brought in from the west side 

 of the valley, and have gradually extended entirely across it, 

 with a very uniform easterly dip. But most of the materials 



composing the sand 

 to determine, appear 



as 



from 



the sandstone was deposited. I will mention one striking es 

 ample. At the footmark locality in Northampton, the npF 

 marks on the fine sandstone are at right angles to the preset 1 

 course of Connecticut river ; and as I was looking at them o# 



